Apparatus for automatic control of tow takeup means by detecting the amount of tow on conveyor

ABSTRACT

Apparatus for automatically detecting changes in the amount of tow on a conveyor and thereby automatically controlling the start or stop of the operation of tow takeup means and maintaining the amount of tow on the conveyor at a specified value.

United States Patent lnventor Tatsurni Tanabe Ehime-ken, Japan Appl. No, 841,813 Filed July 15, 1969 Patented Nov. 9, 1971 Assignee Teijin Limited Osaka, Japan Priority July .23, 1968 Japan 43/51967 APPARATUS-FOR AUTOMATIC CONTROL OF TOW TAKEUP MEANS BY DETECTING THE AMOUNT OF TOW ON CONVEYOR 6 Claims, 1 Drawing Fig.

U.S. Cl ZOO/61.41, 335/205 Int. Cl H0lh 3/16 Field of Search 200/61 .41,

[56] References Cited UNITED STATES PATENTS 2,655,249 10/1953 Feick 198/232 2,932,382 4/1960 James 198/232 3,301,974 1/1967 Hancock ZOO/61.42 3,462,569 8/1969 Schooley ZOO/61.13 3,487,181 12/1969 Bourgault et al. ZOO/61.13 2,280,573 4/1942 Flaws 198/232 Primary Examiner-Robert K. Schaefer Assistant Examiner--M. Ginsburg Attorney-Sherman and Shalloway ABSTRACT: Apparatus for automatically detecting changes in the amount of tow on a conveyor and thereby automatically controlling the start or stop of the operation of tow takeup means and maintaining the amount of tow on the conveyor at a specified value.

APPARATUS FOR AUTOMATIC CONTROL OF TOW TAKEUP MEANS BY DETECTING THE AMOUNT OF TOW ON CONVEYOR This invention relates to an apparatus for automatically controlling tow takeup means by detecting an amount of a tow transferred by a conveyor, running at a constant speed. It is an object of this invention to provide an improved apparatus for automatically detecting the amount of two on the conveyor and thereby automatically controlling the operation of tow takeup means. For instance, when there is a tow on the specified section of the conveyor takeup side followed by takeup means, the tow takeup means operates, and when the tow on said specified section of the conveyor is gone, the operation of the tow takeup means stops automatically. A device detecting the amount of tow is installed above the conveyor, and, at the same time, the operation of the tow takeup means is automatically controlled by said device.

it is common in the textile industry to convey a tow with a conveyor. For instance, synthetic filament tow is heat-set, while being conveyed in a serpentine form on a conveyor after drawing and crimping, and then led to a cutter to be cut into staple fibers or lead to packaging equipment without being cut. in these cases, if the takeup speed is too slow, the two continuously fed after heat treatment overflows the conveyor and falls ofi. On the other hand if the takeup speed is too fast, the serpentine tow on the conveyor runs out and the tow under heat treatment in the heating device is prematurely pulled out, resulting in taking up a defective tow insufficiently heat treated. THerefore it is desired to have the amount of tow to be fed agree completely with the amount to be taken up. However, it is very difficult to adjust the forwarding speed of tow on the conveyor and the tow takeup speed such that the tow amount forwarded agrees completely with that taken up. For this purpose, heretofore the amounts of tow to be taken up are to be slightly higher than those to be forwarded on the conveyor, and only when a serpentine tow is present in a section positioned at a certain distance back from the end of a conveyor on the takeup side, will the takeup means be driven to take up the tow; whereas if the serpentine tow runs out in the specified section of the conveyor on the takeup side, the operation of the takeup means stops. Thus tow forwarding is adjusted by the repetition of the above operations so that a serpentine tow is always present in the specified section of said takeup side.

Now, since there has heretofore not been an accurate detector available to check whether serpentine tow is present in said section or not, an operator used to, in general, watch the tow on the conveyor and manually switch on and off the operation of the takeup means according to the amount of tow on the conveyor. Attempts to automatically control such operations, have utilized photoelectric systems, mechanical systems using limit switches, noncontact proximity switch systems, etc.; however, none of these systems have been accurate and practical.

This invention is characterized by apparatus for detecting such variations in the amount of tow on the conveyor and thereby automatically controlling the operation of tow takeup means. The apparatus includes an arm disposed above the tow-forwarding conveyor, which arm is moved by the tow carried by the conveyor in the tow forwarding direction according to the amount of tow on the conveyor, and a switch which is responsive to movement of the arm to control the tow takeup means.

The drawing is a perspective illustrating a preferred embodiment of this invention.

With reference to the drawing the apparatus of the present invention includes a pair of identical detectors l and spaced in the direction of movement of a conveyor 7. Detectors l0 and 10' include rods 3, 3' rotatably mounted in brackets 2, 2'. The brackets are disposed on supports 1, 1' held by a fixed structure (not shown) and hanging arms 4, 4 are secured to rods 3, 3' and have tips bent in the direction shown by arrows A, A to sense tow carried by the conveyor. It

will be appreciated that, a plurality of hanging arms may be secured to the rotatable rods. Magnets 5, 5' are secured to the upper ends of arms 4, 4', respectively; and reed switches 6, 6' are attached to brackets 2, 2' and fixed at positions near magnets 5, 5'. While magnets 5, 5' are closely adjacent switches 6, 6, the switches are off, and when magnets 5, 5' are moved away from the magnets, the switches are on. Thus it will be appreciated that switches 6, 6' are magnetically controlled. Detector 10 is disposed at a specified distance from the end of the conveyor detector, 10' and is disposed near the end of the conveyor. Detector 10 is hereinafter referred to as the front detector and, detector 10 is hereinafter referred to as the rear detector.

As tow T is forwarded lying in the serpentine from on the conveyor, hanging arm 4 of the front detector is pushed upwards by the tow T; that is, hanging arm 4 is pivoted counterclockwise in the tow forwarding direction. Magnet 5, accordingly, is moved away from switch 6 and switch 6 thereby is turned on. in a short time the tip of tow advances and pushes up the hanging arm 4' of the rear detector, and switch 6' is turned on in like manner. Until both switches 6, 6' are turned on, the tow takeup means (not shown) are not driven.

When the takeup means are driven, the serpentine tow present on the conveyor in the section between the front and rear detectors runs out after the lapse of a certain length of time, because the tow takeup speed of the takeup means is adapted to be somewhat higher than the tow-forwarding speed on the conveyor. Therefore, hanging arm 4 of the rear detector returns to its original position, and switch 6 is turned off.

Since reed switch 6 remains on, tow takeup operation is continued. That is, since the arm 4 is hung down so as to have a distance of a few centimeters between its tip and conveyor 7, tow T being taken up from the section between the front and rear detectors passes through the space between the tip of the arm 4' and the conveyor 7, and the arm 4' is not pushed upward by the tow T being taken up.

In a short time, when the hanging arm 4 of the front detector returns to its original position and switch 6 is turned off, the driving of the takeup means is stopped. With the stoppage of the takeup means, the forwarded tow on the conveyor pushes up, again in turn, hanging arm 4 of the front detector and hanging arm 4' of the rear detector in turn to turn switches 6, and 6' on, resulting in the redriving of the takeup means. By the repetition of such operations, the amount of tow T on the conveyor is controlled so that it always stays between the front and rear detectors in the meandering form. Of course, it will be appreciated that actuation and deactuation of switches 6, 6' may be utilized as desired to provide the desired control.

Each detector may have a plurality of hanging arms arranged transversely of the conveyor advancing direction. In this case, the switches are operated on and/or off as in the previous case, and the staple-cutting speeds or tow-forwarding speeds may be adjusted with these devices. While in the embodiment, when switches 6, 6' were both off, the takeup means was adapted to stop, the tow-forwarding speeds of the conveyor may be converted into any takeup speeds lower than said tow-forwarding speeds without stopping the takeup means. Further an intennediate detector may be installed between the front and rear detectors so that takeup speeds can changed stepwise. Furthermore, only one detector may be used instead of a plurality of detectors.

This invention has, as described above, a remarkable advantage that operation of tow takeup means can be easily controlled automatically with sharp curtailment of labor costs.

lclaim:

1. In apparatus for automatically controlling a tow takeup means in response to the amount of tow carried by a conveyor, detecting means comprising a detector including support means disposed above said conveyor, sensing means pivotally suspended adjacent its upper end from said support means and having a lower end disposed adjacent said conveyor for movement by said tow carried by said conveyor, magnetic means 4. The apparatus according to claim 3 wherein said sensing means of each of said detectors includes a plurality of hanging arms mounted transversely of the conveyor advancing direction.

5. The apparatus according to claim 4 wherein said hanging arms have tips bent in the conveyor advancing direction.

6. The apparatus according to claim 1 wherein said support means includes a rod rotatably mounted in a bracket, said sensing means includes an elongated arm having an upper end attached to said rod and a lower end end bent in the conveyor advancing direction, and said magnetic means includes a permanent magnet carried on said upper end of said arm.

* 16K i t 

1. In apparatus for automatically controlling a tow takeup means in response to the amount of tow carried by a conveyor, detecting means comprising a detector including support means disposed above said conveyor, sensing means pivotally suspended adjacent its upper end from said support means and having a lower end disposed adjacent said conveyor for movement by said tow carried by said conveyor, magnetic means carried by said sensing means and movable therewith, and magnetically operated switch means supported by said support means adjacent said magnetic means, said switch means being controlled by said magnetic means to control the operation of said tow takeup means.
 2. The apparatus according to claim 2 wherein said sensing means includes a plurality of hanging arms mounted transversely of the conveyor advancing direction.
 3. The apparatus according to claim 1 wherein said detecting means includes a plurality of said detectors disposed in spaced relation along the conveyor advancing direction.
 4. The apparatus according to claim 3 wherein said sensing means of each of said detectors includes a plurality of hanging arms mounted transversely of the conveyor advancing direction.
 5. The apparatus according to claim 4 wherein said hanging arms have tips bent in the conveyor advancing direction.
 6. The apparatus according to claim 1 wherein said support means includes a rod rotatably mounted in a bracket, said sensing means includes an elongated arm having an upper end attached to said rod and a lower end bent in the conveyor advancing direction, and said magnetic means includes a permanent magnet carried on said upper end of said arm. 